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Reports <code>while</code> loops that spin on the
value of a non-<code>volatile</code> field, waiting for it to be changed by another thread.
<p>
In addition to being potentially extremely CPU intensive when little work is done inside the loop, such
loops are likely to have different semantics from what was intended.
The Java Memory Model allows such loops to never complete even if another thread changes the field's value.
</p>
<p>
Additionally, since Java 9 it's recommended to call <code>Thread.onSpinWait()</code> inside a spin loop
on a <code>volatile</code> field, which may significantly improve performance on some hardware.
</p>
<p><b>Example:</b></p>
<pre><code>
  class SpinsOnField {
    boolean ready = false;

    void run() {
      while (!ready) {
      }
      // do some work
    }

    void markAsReady() {
      ready = true;
    }
  }
</code></pre>
<p>After the quick-fix is applied:</p>
<pre><code>
  class SpinsOnField {
    volatile boolean ready = false;

    void run() {
      while (!ready) {
        Thread.onSpinWait();
      }
      // do some work
    }

    void markAsReady() {
      ready = true;
    }
  }
</code></pre>
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<p>
Use the inspection options to only report empty <code>while</code> loops.
<p>
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